Hitherto, artificial stone is known to be produced by crushing natural stone, mixing this with resin, grinding and hardening. And, regarding this artificial stone, processes are known to produce stone materials therefrom having the appearance of marble, granite, etc., and furthermore such materials are superior in hardness, strength.
For improving the performance of such artificial stone, adding an optical function using a noctilucent substance as a light storing material, or a fluorescent substance of an ultraviolet ray emitting material, emitting light accompanied by ultraviolet ray absorption, has been proposed.
However, in the case of a conventional noctilucent, or fluorescent artificial stone, mentioned above, only a part of that binder resin component or aggregate exposed on the surface part of artificial stone functions to emit light. Thus, there was disadvantage that light storing material etc. contained inside the formed body of artificial stone does not function to emit light. Fluorescent materials are very expensive and since even the addition of a small quantity raises the total cost of artificial stone product about 3 to 10 times, conventional artificial stone containing internal fluorescent substances is not practical costwise.
On the other hand, if the amount of noctilucent or fluorescent substance is reduced for cost reduction, it follows that the function of light emission or light storage is impaired.
Therefore, in order to improve the light function of artificial stone, the realization of a new artificial stone superior in function and effect, being capable of sufficient light emission, by the use of less noctilucent or fluorescent substance of a light storing material, for cost reduction, has been desired.